Protein diversity in store-operated calcium entry components and their related variants.

Protein diversity is a fundamental biological process that enhances the functional complexity of cellular signaling pathways. This diversity arises through multiple molecular mechanisms such as gene duplication, alternative splicing, and alternative translation initiation, which together expand the proteome landscape. Calcium signaling showcases this diversity, with several channels, pumps, and regulatory proteins expressed as multiple isoforms and variants. Within the store-operated calcium entry pathway, protein diversity is evident in the existence of distinct paralogs of ORAI channels and STIM proteins. The additional presence of numerous isoforms and variants of ORAI and STIM shapes the store-operated calcium entry pathway, providing flexibility to cellular calcium regulation in various contexts. Deciphering how protein diversity modulates store-operated calcium entry function is essential for advancing our understanding of calcium signaling in both health and disease.